1. Field of the Invention
This invention relates to a mat which is laid on the seat of a chair.
2. Description of the Prior Art
When a man is standing, the spinal column forms a gentle S-shaped curve to suspend the internal organs, and the pelvis has an appropriate angle to support the spinal column in its appropriately curved form. If he sits on a chair, therefore, the pelvis fails to maintain its appropriate angle and the spinal column also ceases to maintain its appropriately curved shape. As a result, he stoops forwards, as shown in FIG. 3.
If he keeps a stooping posture for a long time, he will have a number of problems, as will hereinafter be stated:
(1) He may suffer from loss of appetite, or indigestion, as pressure bears upon the internal organs; PA1 (2) He may lose concentration as a result of a reduction in the amount of blood carried to the brain and thereby the amount of nourishment and oxygen carried thereto; and PA1 (3) He may suffer from lumbago, since when he is seated, the lumbar region of his back receives nearly twice as heavy a load as when he is standing.
A special chair has, therefore, been proposed to overcome those problems. It is constructed as shown in FIG. 5, and comprises a forwardly and downwardly inclined seat and a knee rest which is positioned below and forwardly of the seat and is backwardly and downwardly inclined. Because of its special construction, however, this chair is expensive and is not necessarily suitable for common use in an office, or like place.